The blaze covers about 28 square miles north of Wenatchee and is threatening hundreds of structures and has led to periodic closures of US Highway 97A.

Keith Vradenburg, mayor of the small town of Entiat, Washington, said the town is thick with both firefighters and smoke.

"I can't hardly see across the Columbia River," Vradenburg said. "That's about a half mile across it from my house to the other side. So we have a lot of smoke, which we've had for the last several days."

The Mills Canyon fire is the largest of about a half dozen blazes in the Northwest. Most of the fire activity is in central and eastern Washington.